Acoustic diaphragm



April l0, 1928 J. Q. sLYE ET AL ACOUSTIC DIAPHRAGM Filed Deo. 16, 1926 wO W T of Q :S75/e MH Patented Apr. 10, 1928.

UNITEDSTATES PATENT OFFICE.

JOHN Q. SLYE AND RICHARD/H. COFFBEN, 0F WASHINGTON, DISTRICT OFCOLUMBIA.

ACOUSTIC DIAPHBAGM.

Application llled December 16, 1926. Serial No. 155,220.

This invention relates to improvements in sound reproducing instrumentsand more particularly to a nove'l diaphragm for' talking machines, loudspeakers and the llke.

With a view of improving sound reproduction instruments and to obtainbetter results, various kinds of diaphragms lhave been devised. Some ofthese are made up of laminated layers. The present invention relatesmore specifically to diaphragms of the last mentioned type.

One of the objects of the invention is to provide a diaphragm made up ofat least three layers, each playing an important part with tonevibrations in musical records and the like. One layer preferablyconsists of double-faced satin, and this is combined with a second layerof thinly rolled' tin foil, these two layers combining to give rich tonequality to the music and dampening the metallicrin usually present intalking machines an ythe like. The third layer preferably consists of acircular piece of cork which modifies the great friction which isusually aociated with talking machine records.

Wth the foregong objt voutlined and with other objects in view whichwill appear as the description proceeds, the invention consists in t enovel features hereinafter described in detail, illustrated in theaccompanying drawing, and more particularly ointed out in the appendedclaims.

Re erring to the drawing:

Fig. 1 is a face view of a standard talking machine reproducer providedwith the'y improved diaphragm.

Fig. 2 is a vertical sectional view taken on line 2-2 of Fig. 1. l

Fig. 3 is an enlarged vertical sectional view of a portion of thediaphragm, to clearly illustrate the arrangement of the layers.

In the drawing, 1 designates a talking machine reproducer, which may beof any preferred construction, to be combined with the improveddiaphragm, the latter being connected to the usual stylus 3.

As best shown in Fi-g. 3, the diaphragm forming the subject matter, ofthis invention consists of a layer 4.- of textile fabric. We have foundin practice that doublefaced brown satin is particularly suitable for.our purpose, owing to its appearance and` construction. Arranged at therear of the fabric layer, is a layer 5 of thin metallic foil, preferablytin foil, and arranged rearwardly of this layer is a third layer ofdampening material, such as cork. This layer is of smaller size than theother 2 60 layers to permit free vibration of the diaphragm.

In manufacturing this diaphragm, the three layers, while in a flexiblecondition are pressed together and dried by heat, and in actualpractice, we have built u a diaphragm of this character, in the ollowingway:-

We used one thin circular piece of cork 1% inch in diameter; onecircular layer of 70 tin foil of larger diameter rolled ver thinly; andone layer of double-face satin treated on both sides with quick dryingFrench varnish. The layers were superposed, and adhesive placed betweenthe tin 7h oil and cork, and then the laminations were pressed togetherand dried by heat. The resulting diaphragm was placed in a reproducercasing and was found to produce improved' results, re roducing sound4more 80 Shar ly and softly t an the diaphragm now on t e market.

From the foregoing it is believed that the method of manufacture, andthenimproved construction may be clearly understood, and it is obviousthat changes may be made in the details disclosed Without departing fromthe s irit of the invention as expreed in the c aims.

What is claimed and desired to be secured 9o by Letters Patentis:

1. A laminated diaphragm for sound re producers comprising at leastthree layers, one layer of textile fabric, one of metallic foil, andVone of sound dampening material, and adhesive securing said layerstogether.

2. A laminated diaphragm for sound reproducers comprisi ff at leastthree layers, one layer of textile abric, one layer of metallic foil,and one layer of cork, the cork 10o Q 1 ,emee

layer being of smaller diameter than the formed of (zoek, and theintemeiete teg/e11- other layers, and. adhesive seeming said layformedof tmoil,` and adhesive securing said 10 ers together. layers together.

3. A. laminated diaphagm for soulld ren testimony whereof we mx om'isigne.-z

5 prouees compgismg et least three layers, tures,

one outer layer formed of double-faced satin coated on both sides withveemsh7 the JOHN SLYE. other outer ayer being of smaller size andRECHARD H. COFFREN.

